Freshwater is an extremely limited resource – less than 1% of the planet’s water is freshwater in the form of groundwater or surface waters. This already limited resource is being increasingly diminished by drought, pollution and overuse. The World Health Organization estimates that “[b]y 2025, half of the world population will be living in water stressed areas.”

According to the United Nations Department for Economic and Social Affairs(UNDESA), “[d]eclining water quality has become a global issue of concern as human populations grow, industrial and agricultural activities expand, and climate change threatens to cause major alterations to the hydrological cycle.” UNDESA reports that “Every day, 2 million tons of sewage and other effluents drain into the world’s waters, and that “[e]very year, more people die from unsafe water than from all forms of violence, including war.”

In the U.S., groundwater supplies between 25% and 40% our drinking water and feeds the surface water flows that sustain wetlands, streams, rivers, lakes, and reservoirs. Unfortunately, groundwater supplies are being rapidly depleted, as in the case of the Ogallala Aquifer which underlies eight U.S. states, and polluted resulting in loss of drinking water supplies, polluted surface waters, and public health problems. Cleaning up groundwater pollution is very expensive and, in many cases, impossible.

In the U.S., most people get their drinking water from surface water in streams, rivers, lakes, or reservoirs, and more than one-third of the population obtains their drinking water in whole or in part from small headwater streams which make up more than 50% of the total stream miles in the U.S. Protection of these vulnerable headwater streams is essential to restoring water quality in downstream waters because they serve essential ecological functions and feed into larger systems of surface waters that eventually form large rivers, lakes, reservoirs, estuaries, and oceans.

Image: US Environmental Protection Agency

UNDESA reports that eutrophication due to agricultural runoff, domestic sewage (also a source of microbial pollution), industrial effluents and atmospheric inputs from fossil fuel burning and bush fires is the “most prevalent” water quality problem on earth. While noting that this long-standing problem has not been solved, the United Nations Environment Program reports that we are now facing new threats from climate change, the decommissioning and removal of dams from waterways, the discharge of newer and more chemicals into surface waters, identification of new and emerging pathogens, and the introduction of non-native or invasive species to aquatic ecosystems.”

Image: Louisiana Universities Marine Consortium

Globally, water pollution is difficult to address due to widely divergent laws, resource limitations, industrial and agricultural concentrations, political concerns, the nature of the pollution problem, and many other factors. While in the U.S the CWA has been very effective in controlling pollution in some respects, many of the major U.S. waterways remain polluted, and by some indications pollution appears to be increasing. For example, while water quality in a large percentage of our nation’s waters has not been assessed, the most recent available data from EPA in the U.S. EPA Watershed Assessment, Tracking and Environmental Assessment report shows water pollution in assessed waters has impaired 558,999 river/stream miles, 12,197,097 lake acres, 26,120 sq. miles of estuarine waters, 7,204 miles of coastal waters, and 53, 270 sq. miles of the Great Lakes.

Pollution, beach closures, fish kills, and fish advisories in U.S. coastal waters, including the Great Lakes, has been a recognized as a national problem since at least 2000 due to the critical value of these waters to economic and environmental interests, and the pervasive problems caused by nutrient enrichment, aquatic habitat and species degradation, pathogens, toxic contaminants, and harmful algal blooms. Unfortunately, these severe water quality problems remain unaddressed even in major waterbodies like the Gulf of Mexico, the Chesapeake Bay, Lake Erie, and the Tar-Pamlico Estuary.